Alloy of aluminium.



UNITED STATES PATENT LOFFl'CE.

LUDWIG MACH, on ENA, GERMANY.-

ALLOY OF ALUMINIUM.

srnonrnnrrlou forming part of Letters Patent No. 625,084, dated July 18, 1399.

proved alloy of aluminium and magnesium.

Here'tofore, as is known to those familiar with the art, a most valuable quality of alu minium (its small specific gravity, 2. 64) could notvbe made use of to the degree desired, be-

offers great difficulties to being worked.

of aluminium generally made use of.

work the pure aluminium with cutting-tools. The faces worked show tears. composed of short splinters. The tools do not cut, but tear. Files are stopped upafter a few touches and are rendered ineffective, so that the hand manipulatingthe file has more the feeling of inefiiectually rubbing than that of shaping chips. In this respect the pure aluminium is inferior in these qualities even to pure copper, which, as is known,

Hence for many years experiments have been directed to the improvement of the technological qualities of the aluminium by adding heavy metalssuch as copper, nickel, &c.- naturally not Without entailing a correspondin g increase of specific weight. Although the chief advantage of the aluminium was thereby partly sacrificed, the improvement in resultobtained did not answer expectations, it being impossible to turn to shape, to mill.

clean or satisfactory faces, or to cut sharp threads on pieces Worked from these alloys Further, it was found to be impossible to work them with good effect with fine files.

This invention relates to an alloy of aluminium which allows of the working by cut ting-tools in a perfect manner and yet diminishes thespecific Weight of the pure aluininium.

It has been demonstrated by numerous experiments that magnesium, with its lighter specific gravity, (1.74,) alloyed with aluminium in certain proportions gives the latter those qualities with respect to its mechanical working and strength which the pure aluminium does not possess. From these experiments it resulted that in order to produce The chips are Application filed February 25, 1899. Serial No. 706 ,848 (do specimens.)

the qualitiesmentioned as little as ten and no more than thirty parts, by weight, of magnesium maybe added to one hundred parts of aluminium and that the proportion of ten to twenty-five parts of magnesium to one hundred parts of aluminium was the most advantageous.

"If one hundred parts of aluminiumare alloyed with ten parts of maghe'sium,.the alloy has about the same mechanical qualities as rolled zinc. An alloy of one hundred parts of aluminium and fifteen parts magnesium corresponds to good foundry-brass, While an alloy of one hundred parts of aluminium and of twenty parts of magnesium gives the metal the character of a softer red brass or a brass wire hard drawn, and, finally, an alloy of twenty-five parts of magnesium and one hundred parts of aluminium represents the qualities of usual red brass.

Y This alloy maybe founded in a thin fusible state. The pieces founded exhibit long curls of chips in turning or boring. Threads can be cut with sharp profiles, and the bore-holes are very fine and neat. The file makes a fine and regular touch or cuts without tearing or becoming stopped up. In filing the usual characteristic noise is heard. I Heretofore only coarse or middling files could be employed, naturally at the cost of exactness. permits the use even of the finest files.

The pure aluminium can be out with a knife like zinc, while the new alloybehaves like a piece of red brass beneath the edge of theknife. Yet these alloys, especially the softer alloys-one hundred parts aluminium and ten to fifteen parts magnesium-are very ductile and can be forged in a cold state, milled to plates, drawn to tubes and wire, and possess, therefore, the Very valuable qualities of the pure aluminium.

The hardness and strength of the new alloy are so eminent that even axes, cock-pegs, &c.

can be manufactured from it. The polish can be carried to brilliancy and is of an extraordinary resistance to the influence of the atmosphere. The color of the alloy is nearly silver white, differing from that of thepure aluminium, the color of which is somewhat unsightly. Besides these valuable workable qualities this new alloy of aluminium and magnesium possesses the invaluable superi- This alloy ority that the specific weight not only is not increased, but is even reduced.

To this alloy of aluminium and magnesium heavy metals and alloys of them may be added-such as copper, nickel,-tungsten, and German silver; but except when intended for special purposes such an addition is not advisable, because, on the one hand, the specific weight of the alloy is increased and, on the other hand, one can attain, even to the finest modifications, all the mechanical qualities by the aluminium magnesium alloy, such as hardness and workable qualities; It has become evident that with such additions the best results are obtained if only as much of the heavy metal is added to the alloy of aluminium andmagnesium so long as the specific gravity of the pure aluminium be not exceeded.

. An addition of heavy metals to alloys .containing more than twenty parts of magnesium to one hundred parts of aluminium would be quite useless, because the unusual hardness and initial brittleness characteristic of this addition would be disadvantageous to the working of the alloy. Experiments for alloying aluminium with magnesium had been begun at the time when aluminium was discovered. Wohler(A1maZen der Ohemt'e 'ZLlld Phcm'mac'ie, 1866, Vol. 138, p. 253) fused these two metals togetherin the proportions represented by Al Mg, formingan alloy with 69.2 per cent. of aluminium. The product was a tin-white mass, very brittle, igniting at red heat, and burning with a white flame similar to magnesium alone. The alloy in the proportions Mg Al,containing thirty-six per cent. of aluminium, was malleable, but completely destroyed by leaving in water for a day without any evolution of hydrogen. \Vohler stated his opinion with regard to these alloys as follows: Both these mixtures ap-' peared to contain a compound of definite composition, for when treated with a solution of salammoniac they disengaged hydrogen abundantly and deposited a brilliant, tin-w white metallic powder. The solution contained magnesium chlorid, while the residue was rich in aluminium and appeared to produce some aluminate of magnesium, which clouded the solution. The metallic residue was washed with water, again treated with Sal-ammoniac solution, and then with solution of caustic soda until it no longer evolved hydrogen. This residue was about one-third the total alloy and was insoluble in both the above reagents. sparks when thrown into a flame.

Parkinson, (Jom'nd'lfitr Practischc Chemic, Vol. 101, p. 375,) after his experiments with magnesium alloys, says: None of the mag It burned with brilliant nesium-aluminium alloys promises any practical utilization, and this at a time when VVohlers experiments had long been known.

Muspratt (Techm'sche O/lTltt-, edition 1V, Vol. 5, p. 1026) comprises the result of the experiments made by )Vhite, WVanklyn and Chapman, Parkinson, and Mellor, so that all the alloys are very brittle and are more or less oxidized by the air and decomposed water to a certain extent. Even to the present time this view has remained unchanged. This is seen by the circumstance that a modern author, such as Richards, who has thoroughly treated of aluminium has .nothing else to mention of the alloy of aluminium and magnesium but the results from the experiments of Wohler, enumerating, as he does, the same compounds Al Mg (alloy with 69.2 per cent. Al) and Mg Al (alloy with thirty-six per cent. Al) and the same result. as tvohler, and this at a time when the practical importance was established beyond all doubt, which wasnot the case at the time of Wohler, (cf. Richards,

Aluminium, edition II, p. 400.)

Once more, magnesium in connection with aluminium is mentioned in the Englishspecification No. 21,575, of 1895. 'To obtain an alloy of aluminium possessing a greater tenacity than pure aluminiu m has,alu minium is mixed with tungsten or magnesium as acopper-tintungsten alloy or copper-tin-magnesium al- 10y. Magnesium is containedin vanishing quantities (four percent.) in this alloy, of which four to ten per cent. are added to the aluminium, so as to leave still smaller quantities in the final alloy.

Having now described my invention, what I claim as new, and desire to protect by Letters Patent, is

1; An aluminium-magnesium alloy herein described containing aluminium and 1nagne sium in the proportions of one hundred parts of aluminium to between ten and-thirty parts of magnesium substantially as and for the purpose described.

2. An alloy comprising one hundred parts of aluminium, ten to thirty parts of magnesium, with copper, nickel, tungsten, and zinc, substantially as described.

3. An alloyincluding onehundred parts of aluminium, ten to thirty parts magnesium, and some heavier metal or metals, said alloy having a specific gravity no greater than aluminium.

In testimony that I claim the foregoing as my invention I have signed my name in presence of two subscribing witnesses.

. LUDWIG MACH.

Witnesses:

ALVESTO S. IIOGUE, W OLF PAULI. 

